1. Field of the Invention
The present invention generally relates to sailing equipment. The invention more specifically relates to a sail handling mechanism and method for raising and lowering the sail.
2. Background
Sails used on sailboats have historically been generally triangular in shape. The forward upper corner is called the head, the forward lower corner is called the tack, and the rear corner is called the clew. The forward edge of the sail between the head and the tack is called the luff, the lower edge of the sail between the tack and the clew is called the foot, and the aft edge between the head and the clew—the diagonal edge—is called the leach.
FIG. 1 shows a prior art sail 100. In a typical configuration, the foot of the sail is attached, at least semi-permanently, to the boom 110. The luff of the sail is attached to the mast 120 by a variety of means, the choice of attachment mechanism being determined generally by the sizes of the boat and of the sail. For relatively large sails, multiple sail slides 130 may be attached to the luff at discrete intervals. The sail slides 130 are received in a compatible track which is attached to the mast. The sail slides travel up and down the mast when the sail is raised and lowered (unfurled and furled).
Much of the load in the unfurled sail is concentrated at the head. It is therefore common practice to heavily reinforce the head corner, and to attach to the head a rigid plastic or metal board or a steel ring called a headboard 140. The headboard may then be attached to the track with one or more sail slides 130. More typically, the headboard is attached to the track with a special type of slide called a headcar or a headboard carriage.
To unfurl a sail, the sail is hauled aloft by raising the headcar and the sail slides along the track. The headcar is raised with a line, called a halyard 150, which is fastened to the headboard 140 and passes through a mast truck 160 at the top of the mast 120. One of the advantages of using multiple sail slides 130 to furl and unfurl a sail is that when the sail is dropped (furled), the slides 130 collapse against each other into a stack. The sail is folded (flaked) between the slides 130 and rests on top of the boom 110.
The most aerodynamically efficient shape for a sail is an ellipse, which is approximated by the trapezoidal shape utilized in most current art sails. Sails with this configuration may be referred to generically as squarehead sails. To maximize the efficiency of the sail, the sailmaker cuts the leach in a curve, called the roach, to provide an expanded sail area aft of the geometric triangle defined by the three corners of the sail. The modified shape allows additional power to be generated from the sail.
To support the large sail area aft of the geometric triangle and to eliminate fluttering in the otherwise unsupported leach, a common practice is to distribute stiffening elements, called battens 170, along the leach. The battens 170 are made of wood, fiberglass, or other suitable materials, and are oriented roughly parallel to the boom 110 so that when the sail 100 is furled, the battens 170 lie in a tight bundle on top of one another along the boom 110.
The battens 170 may extend from luff to leach, with an aft leach end of each batten 170 secured in a pocket on the leach, and a forward luff end connected to a special sail slide 130 called a batten car. The batten cars are designed to resist the compression forces in the batten 170 caused by the tension in the curved leach of the unfurled sail, and to reduce friction in the sail furling/unfurling mechanism. The use of the specially designed batten cars has led to increased height of the stack of slides, commonly called the stack height, when the sail is furled.
The increased stack height becomes an issue only because in order to support the upper aft corner of a squarehead sail, the uppermost batten 170 may be set at a steep angle relative to the foot of the sail 100. The angle helps the batten 170 to resist the compression forces caused by the tension in the sail fabric. A triangle of sail cloth—bounded by the headcar, the uppermost batten car, and the leach end of the uppermost batten 170—supports the uppermost batten 170 when the sail 100 is being dropped, so that the uppermost batten 170 may not properly fold down onto the boom 110. Therefore in order to properly furl the sail 100, the uppermost batten 170 must be detached from its diagonal position, either by removing the aft end of the batten 170 from the leach pocket, or by detaching the headboard 140 from the headcar.
The requirement of detaching the uppermost batten 170 can be problematic because with even fairly common boat and sail dimensions, it is not uncommon for the combined boom height, sail slide stack height, and length of the uppermost batten 170 to leave the leach end of the uppermost batten 170 and the headboard at a height—which may be twelve feet or more—above the deck that is unreachable by anyone standing on the deck.
On racing boats it is common to have a large crew who are used to climbing the mast for various reasons. It is therefore no great problem to send a crewman up the mast far enough to either remove the diagonal batten from the leach pocket, or to detach the headboard from the headcar to allow the sail to be properly furled, and to reverse the procedure when the sail is hoisted. However, on a cruising boat without a large crew, it is both inconvenient and potentially dangerous to have to climb the mast to set or furl the sail. To date, this problem has limited the application of the more efficiently constructed sails, as described above, on cruising boats.
Therefore, for the safety and convenience reasons discussed above, there is a need for a mechanism that allows an operator of a boat with relatively large sails to attach and detach a headboard 140 from a headcar without leaving the deck of the boat.